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Harmonical and modal analysis to determine the anisotropic properties of aviation composite materials

100%

Acopyan A. , Axenov V. , Shevtsov V. , Soloviev A. , Tamarkina E.

tom Vol. 14, No. 3

11-18

The value of all composite elastic modules has the crucial influence on dynamic behaviour of aviation load-bearing structures. Numerous experimental techniques and standards are used to characterize the elastic properties of polymeric composite materials. Among this is the large group of static tests, acoustic methods based on longitudinal, lateral or shear surface sound wave speed measurements and also on vibrating surfaces amplitude measurements. However, preparation specimens for static test with shape required by standards not always possible from already manufactured piece. Again the designated dynamic experiment introduces difficulties of investigated specimen acoustic isolating, impossibility of some required wave type excitation and performing of displacements field measurement with guaranteed precision. In this study an acoustic method is developed using the measure of all specimen's eigenfrequencies in a certain frequency range. Small rectangular composite specimen is excited by glued piezoelectric actuator and response is measured by piezoelectric sensor. Preliminary performed finite-element (FE) analyses serve to think the vibration natural modes of linked mechanical system - specimen and piezoelectric element. In this FE analyse the rough estimations of all elastic constants obtained from other independents (as a rule static) experiments were used. Further the amelioration of initial elastic modules was performed. Thereby the target nonlinear functional dependent on all quest modules was minimized by genetic and (or) Levenberg-Marquardt algorithm.

Numerical simulation of space charge effects in the sector cyclotron

86%

Onischenko L. , Samsonov E. , Aleksandrov V. , Shevtsov V. , Shirkov G. , Tuzikov A.

tom Vol. 48,suppl.2

45-48

To study the effects of space charge in cyclotrons and synchrocyclotrons the code PHASCOL is developed. A method of large (macro)particles is realized in this code. The complete equations of motion of the charged particle in electromagnetic field of accelerator are integrated taking into account the three-dimensional self-electric field of beam. Two methods were used for the calculation of the beam field: the particle-to-particle method and the particle-in-cell one. The results of calculations which illustrate space-charge effects on the parameters of beam in the process of acceleration are given. Both methods have shown a similar influence of space charge on the beam.